Tetris (Тетрис) is a video puzzle game originally designed and programmed by Alexey Pajitnov in June 1985, while working for the Dorodnicyn Computing Centre of the Academy of Science of the USSR in Moscow. He derived its name from the Greek numerical prefix "tetra-", as all of the pieces contain four segments, and tennis, Pajitnov's favorite sport.
The game (or one of its many variants) is available for nearly every video game console and computer operating system, as well as on devices such as graphing calculators, mobile phones, portable media players, PDAs and even as an Easter egg on non-media products like oscilloscopes. It has even been played on the sides of various buildings, with the record holder for the world's largest fully functional game of Tetris being an effort by Dutch students in 1995 that lit up all 15 floors of the Electrical Engineering department at Delft University of Technology.
While versions of Tetris were sold for a range of 1980s home computer platforms, it was the hugely successful handheld version for the Game Boy launched in 1989 that established the reputation of the game as one of the most popular ever. Electronic Gaming Monthly's 100th issue had Tetris in first place as "Greatest Game of All Time". In 2007, Tetris came in second place in IGN's "100 Greatest Video Games of All Time".
A pseudorandom sequence of tetrominoes (sometimes called "tetrads" in older versions) - shapes composed of four square blocks each - fall down the playing field. The object of the game is to manipulate these tetrominoes, by moving each one sideways and rotating it by 90 degree units, with the aim of creating a horizontal line of blocks without gaps. When such a line is created, it disappears, and any block above the deleted line will fall. As the game progresses, the tetrominoes fall faster, and the game ends when the stack of tetrominoes reaches the top of the playing field and no new tetrominoes are able to enter.
Tetris game manuals refer to the seven one-sided tetrominoes in Tetris as I, J, L, O, S, T, and Z - due to their resembling letters of the alphabet - but players sometimes use other names for the pieces, such as "stick" for I or "snake" for S. All are capable of single and double clears. I, J, and L are able to clear triples. Only the I tetromino has the capacity to clear four lines simultaneously, and this is referred to as a "tetris." (This may vary depending on the rotation and compensation rules of each specific Tetris implementation. For instance, in the Super Rotation System (see below) used in many recent implementations, certain rare situations allow T, S and Z to 'snap' into tight spots, clearing triples.)
| Piece | Vadim Gerasimov's Tetris 3.12 | Microsoft Tetris | Sega/Arika (TGM series) | The New Tetris and Kids Tetris | SRS (Tetris Worlds and Tetris DS) | Atari/ Arcade | TETЯIS The Soviet Mind Game |
|---|---|---|---|---|---|---|---|
| I | red | red | red | cyan | cyan | red | red |
| J | white | magenta | blue | blue-violet | blue | yellow | orange |
| L | magenta | yellow | orange | magenta | orange | magenta | magenta |
| O | dark blue | cyan | yellow | light grey | yellow | blue | blue |
| S | green | blue | magenta | green | green | cyan | green |
| T | brown | gray | cyan | yellow | purple | green | olive |
| Z | cyan | green | green | red | red | orange | cyan |
The scoring formula for the majority of Tetris products is built on the idea that more difficult line clears should be awarded more points. Nintendo's implementations on the NES, Game Boy, and SNES use what is probably the most widely recognized system.
Nearly all Tetris games allow the player to press a button to increase the speed of the current piece's descent, rather than waiting for it to fall. If the player can stop the increased speed before the piece reaches the floor by letting go of the button, this is a "soft drop"; otherwise, it is a "hard drop". (Some games allow only soft drop or only hard drop; others have separate buttons.) Many games award a number of points based on the height the piece fell before locking. If a piece is manually dropped x lines and locked, these versions will typically award points proportional to the number of lines that the player accelerated the piece. If a piece is not accelerated at all the player will gain no points for that piece unless a line is made.
In many games, an animation will complement scoring. For example, in the Game Boy Tetris and Game Boy Color Tetris DX, when the player finishes the A-Type game with at least 100,000 points, the game displays a cut scene of a rocket lifting off from a launch pad; higher scores produce a larger rocket. When playing Mode B, completing the game at any of the level 9 stages rewards you with dancers and musicians. Completing level 9 with the height setting at 5 gets a large NASA-styled shuttle. In the NES version, a rocket takes off from a platform (the higher your score, the larger the rocket) while Moscow is visible in the distance. If you get over 125,000 points, a UFO is in place of the rocket, but instead of taking off, it sits there and Moscow takes off.
Tengen (the console software division of Atari Games), regardless, applied for copyright for their Tetris game for the Nintendo Entertainment System, loosely based on the arcade version, and proceeded to market and distribute it under the name TETЯIS: The Soviet Mind Game (with faux Cyrillic typography incorporating the Cyrillic letter Ya), disregarding Nintendo's license from Elorg. Nintendo contacted Atari Games claiming they had stolen rights to Tetris, whereupon Atari Games sued, believing they had the rights. After only four weeks on the shelf, the courts ruled that Nintendo had the rights to Tetris on home game systems, and Tengen's TETЯIS game was recalled, with an unknown number of copies sold. Nintendo released their version of Tetris for both the Famicom and the Game Boy (the Game Boy version was developed by Bullet-Proof Software, Inc., who held the Japanese license, despite Nintendo's license to the game) and sold more than three million copies; some players considered Nintendo's NES version inferior because it lacked the side-by-side simultaneous play of Tengen's version, but Nintendo's Game Boy Tetris became arguably the most well-known version of Tetris. The lawsuits between Tengen and Nintendo over the Famicom/NES version carried on until 1993. Sega also released a Tetris game for the Mega Drive, however the ensuing blitz of litigation ensured that it was hastily withdrawn - possibly before it even reached shop shelves. A handful of copies remain, which now change hands for as much as 800,000 yen ($6600) making it probably the most expensive Tetris game in the world. Pajitnov himself made very little money from the deal even though Nintendo was able to profit from the game handsomely. In 1996 when Russian restrictions expired, he and Henk Rogers formed The Tetris Company LLC and Blue Planet Software in an effort to get royalties from the Tetris brand, with good success on game consoles but very little on the PC front. The Tetris Company (TTC) managed to secure trademark registrations for the Tetris mark in several countries and has licensed the brand to a number of companies, but courts have not decided on the legality of tetromino games that do not use the Tetris name. Blue Planet was later purchased by JAMDAT Mobile, in turn purchased by Electronic Arts. According to circulars available from the United States Library of Congress, a game cannot be copyrighted (only patented), which would invalidate much of TTC's copyright claim on the game, leaving the trademark on Tetris as TTC's most significant claim on any government-granted monopoly. Some players prefer Tetris brand games; others prefer homemade tetromino games downloaded from the Internet, which are given names such as "N-Blox" or "Lockjaw" so as not to infringe trademarks. In late 1997 and in mid-2006, TTC's legal counsel sent cease and desist letters to web sites that misused the Tetris trademark to refer to homemade tetromino games.
Tetris has been subject to many changes throughout releases since the 1980s. It is difficult to place a standard on the game, as newer releases frequently progress it either to make the game better or to keep players interested. Newer Tetris games have made the trend of pace rather than endurance. Older releases such as Game Boy or NES Tetris offer records according to points. Since the meter for points is set to only a certain number of digits, these game's records can be "maxed out" by an experienced player. The next big Game Boy release after Tetris, Tetris DX, in marathon mode — comparable to mode A in previous releases — allowed an additional digit for the point meter. Even so, players still maxed it to 9,999,999 points after hours of play. For The New Tetris, world record competitors have spent over 12 hours playing the same game. It is probably for this reason of seemingly everlasting play that in both Tetris DX and The New Tetris, the new modes sprint and ultra were added. These modes require the player to act under a timer — either to gain the most lines or points in that time. Recent releases like Tetris Worlds did away completely with point records. This particular game kept records by how fast a certain number of lines could be cleared depending on the level. A drawback of this deviation, along with some other newer features, is that many traditional players rejected these advances all together. Critics of Tetris Worlds said it was broken due to how a piece is able to hover over the bottom for as long as a player needs; although, players of the game generally do not mind this feature because exploiting it will only hinder play, which is unfavorable to making a record time. Tetris LLC has been juggling different features with different modes of play in past years trying to satisfy traditional and newer players alike.
There are many different modes of play added in recent years. Modes appearing in more than one major release include: classic marathon (game A), sprint (otherwise game B or 40 lines), ultra, square, and cascade.
The field dimension of Tetris is perhaps the least deviated among releases, with the exception of some releases on handheld platforms with small screens. (For example, the Tetris Jr. keychain has 8 columns and 12 rows.) It is almost always 10 blocks wide by 20 blocks high. However, the original Tetris for Game Boy is an exception with a 10 by 18 field of play. The field height may have been decreased to fit within the Game Boy screen. As a result, Tetris for Game Boy had an increased level of difficulty compared to some of its counterparts. Game Boy Tetris is also subject to faster speeds at lower levels.
Traditionally, blocks spawn within the four most central columns and the two highest rows. The I tetromino occupies columns 4, 5, 6, and 7, the O tetromino occupies columns 5 and 6, and the remaining 5 tetrominoes occupy columns 4, 5 and 6 (or in some especially older versions 5, 6, and 7). In some more recent games, pieces spawn above the visible playfield.
In traditional games, a level-up would occur once every ten lines are cleared. During a level-up, the blocks fall slightly faster, and typically more points are given. In some newer games such as Tetris Worlds, the number of lines required vary upon each new level. The fall speed also varies but is usually no more than 20 milliseconds faster for each step per level. For example, NES Tetris operates at 60 frames per second. At level 0, a piece falls one step every 48 frames, and at level 19, a piece falls one step every 2 frames. This means for each level, pieces fall 16 milliseconds faster per step. Level increments will either terminate at a certain point (Game Boy Tetris will top off at level 20) or will increase forever yet not increase in speed after a certain point. NES Tetris will level up in until the speed of level 29 (due to frame restrictions, pieces are not capable of dropping faster than this), but tool-assisted emulation will show that the level indicator will increase indefinitely-- eventually leading to a glitch where the meter displays non-numeric characters. Modern games such as Tetris the Grand Master or Tetris Worlds, at their highest levels, opt to drop a piece more than one row per frame. Pieces will appear to reach the bottom as soon as they spawn. As a result, a hover or slide feature is often implemented into these games to help deal with an otherwise unplayable fall speed. In some games, the hover time is regenerated after a piece is moved or rotated.
Soft drops were first implemented in Nintendo releases of Tetris so that pieces would be able to drop faster while not lock as to slide into gaps. The other option is hard dropping, which originated in early PC games such as Microsoft Tetris, a game developed by Dave Edson and bundled with Microsoft Entertainment Pack. With hard dropping, a piece falls and locks in one frame. Newer Tetris games feature both options. Some games have their locking roles reversed, with soft dropping making the pieces drop faster and locking down, and hard dropping making the pieces drop instantly but not lock.
Single direction rotation is an older restriction that has since been ruled out in nearly every new official release by the favor of separate buttons for clockwise and one for counter clockwise rotation. In traditional games, the unsymmetrical vertical orientation I-, Z-, and S-pieces will fill the same columns for each clockwise and counter clockwise rotation. Some games vary this by allowing two possible column orientations: one for counter clockwise and one for clockwise rotations. Double rotation, only seen in progressive clones such as Quadra and DTET, rotates the piece 180 degrees.
One of the features most appreciated by professional players, is the ability of rotating the pieces even if these touch the left or right walls. In the NES version, for example, if a Z piece is "vertically" aligned and falling touching the left wall, the player cannot rotate the piece, giving the "bad feeling" that the "rotate buttons" are locked. In this situation, the player has to move the piece one position to the right and then rotate it to make the piece "horizontally aligned", losing then a precious time. Proper implementations of this "rotating feature" appear typically, among other, in the Atari Tetris Arcade version (MAME: atetris)
Piece preview allows a look at the next spawn. This feature has been implemented since the earliest games, though in those early games, having the preview turned on made the score increase more slowly.
The New Tetris and The Next Tetris are the first official Tetris games to feature multiple piece previews, showing 3 in advance. Tetris Worlds for PCs and game consoles add 5 more, while the GBA version retaines the 3 piece preview. Tetris DS uses the 6-piece preview.
The "phantom piece" (referred to in some versions, such as the Tetris Mania cell phone game, as the "ghost") is a feature that shows an obscuration in the shape of the current piece over where that piece would drop. The feature disposes with the old problem of misdrops and is relatively new.
Hold piece is an optional ability to reserve a piece for later use, allowing a player to either avoid undesirable pieces or save desirable ones, usually the I piece or a piece needed to complete another goal. Some clones featured it as a powerup that the player could earn and use once. A hold piece available to the player at all times was first featured in The New Tetris. Games that have hold piece generally activate it when the player presses both rotate buttons simultaneously or when the player presses a dedicated button, depending on the game. When hold piece is activated, it causes the falling piece to move to the top and trade places with the hold piece. However, the feature cannot be activated twice in a row; a piece released from the hold must be dropped into the well.
Initial rotation and Initial hold are features that make the game accept rotation/hold button inputs while the next piece is still in the preview area. With initial rotation, when the player holds down the rotation button after the previous piece has locked down but before the next piece comes into the well, the next piece will come into the well in an already rotated state. Initial hold works similarly, as the piece will be already swapped with the hold piece when it enters the well. Initial rotation and Initial hold first appeared in the Tetris: The Grand Master series.
Tetris DS features wireless on-line play through the Nintendo Wi-Fi Connection system. This new version also takes advantage of the touch screen in the added "Touch Mode," which has no time limit. Instead, every block is already placed in a tall tower, and the player uses the stylus from the Nintendo DS to shift blocks left and right and, in earlier towers, rotate blocks. The goal is to clear enough lines so that a cage of balloons reaches the ground. (This mode is themed on the NES video game Balloon Fight, hence the cage of balloons.)
Tetris DS also introduces the Metroid-themed "Catch Mode." In this mode, the pieces still fall downward, but the stack is moved and rotated instead. As the falling pieces bump against the stack, they get clustered into it. To clear blocks, there must be a solid area of the stack that's 4x4 or larger. When this happens, the blocks glow and the music changes. After ten seconds or upon pressing the X button, these blocks disappear and shoot a laser beam in a plus-shape, the horizontal part equal to the number of rows cleared and the vertical equal to the columns. This laser beam will destroy falling blocks and Metroid enemies in its path. The parts of the stack not hit by the laser beam will be pulled in towards the center of the stack after the laser beam dies. If a piece falls below of the bottom screen, the stack hits a falling block while rotating, or the stack hits a Metroid, the stack loses Energy. The player loses if the stack runs out of Energy or if the stack becomes so large that it can no longer fit on the bottom screen.
The Tetris arcade game offered different "puzzles" for selected rounds. The first three rounds are played normally, with no obstacles. At the start of round 4, eight bricks are placed vertically along each side of the well. Round 5 begins with ten bricks scattered throughout the bottom five rows. Round 6 begins with twenty bricks arranged in a pyramid. In rounds 7 through 9, the well starts out empty but single bricks will appear at random on top of your puzzle each time a piece lands that does not clear any lines, potentially thwarting any advance planning you may have done. In rounds 10 through 12, incomplete "garbage" lines will randomly pop up underneath your puzzle, pushing the puzzle upward, when a piece lands without clearing any lines. Rounds 13 through 15 begin with more blocks arranged in predetermined patterns, and the cycle continues throughout the remaining rounds in the game in groups of three.
Because of its popularity and the relatively simple code required to produce the game, a game with nearly the same rules as Tetris is often used as a hello world project for programmers coding for a new system or programming language. This has resulted in the availability of a large number of ports for different platforms, most of which are not endorsed by The Tetris Company and are given away freely. For instance, µTorrent and GNU Emacs contain tetromino stacking games as easter eggs.
The question Would it be possible to play forever? was first encountered in a thesis by John Brzustowski in 1988 and has been more recently investigated in published articles by Walter Kosters. The conclusion reached was that a player is inevitably doomed to lose.
The reason has to do with the S and Z tetrominoes. If a player receives a large sequence of S tetrominoes, the naïve gravity used by the standard game eventually forces the player to leave a hole in a corner.
Suppose that player then receives a large sequence of Z tetrominoes. Eventually, that player will be forced to leave a hole in the opposite corner without clearing the previous hole. Back and forth, the holes will necessarily stack to the top. If the pieces are distributed randomly, this sequence will eventually occur. Thus, if played long enough, and the random number generator is theoretically perfect (or an "evil" algorithm is used instead of it), any player will lose the game.
Practically, this does not occur in most of Tetris variants. Some variants allow the player to choose to play with only S and Z tetrominoes, and a good player may survive well over 150 consecutive tetrominoes this way. On an implementation with an ideal uniform randomizer, the probability at any given time of the next 150 tetrominoes being only S and Z is one in (2/7)150 (approximately 2×10-82). Most implementations use a pseudorandom number generator to generate the sequence of tetrominoes, and such an S–Z sequence is almost certainly not contained in the sequence produced by the 32-bit linear congruential generator in many implementations (which has roughly 4.2 × 109 states). In fact, newer Tetris brand games from 2001 and later tend to follow a new guideline such that the randomizer generates all seven tetrominoes in a permutation at one time, guaranteeing an even distribution over the short term, and this randomizer allows the player to continue a game indefinitely in theory, often clearing all blocks from the playfield. On the other hand, the "evil" algorithm in Bastet often starts a game with a series of more than seven Z pieces.
On the Game Boy version of Tetris the player can only get as much as 999999 score, though the game will continue playing.
Recent versions of Tetris such as Tetris Worlds allow the player to continuously rotate a block once it hits the bottom of the playfield, without it locking into place (see Easy spin dispute, above). This permits a player to play for an infinite amount of time, though not necessarily to land an infinite number of blocks.
Several of the subproblems of Tetris have been shown to be NP-complete.
In 2007, the video game website GameFAQs hosted its 6th annual "Character Battle", in which the users nominate their favorite video game characters for a popularity contest in which characters participate. The L-shaped Tetris piece (or "L-Block" as it was called) entered the contest as a joke character, but on November 4, 2007, it won the contest.
In Japan, a hugely popular live-action game show called Brain Wall ran for a number of seasons. Contestants would be assigned to teams (Red or Blue) and paired with recurring characters. Each team would then, in turn, face a wall of painted styrofoam with a Tetris-like shape carved out. The wall would advance on the contestant, who must pass through the opening by posing, squeezing or jumping. Later levels have a pool of water at the end of the run (the effect being to force the contestant into the pool if they fail.) The recurring characters provide running commentary, built-in rivalry and comic relief. Clips from the series are available on the Internet, under the show's English nickname "human Tetris" A variant of this game show was ported to Argentina as well, called "El muro infernal" ("The infernal wall" in Spanish).
In Thomas Pynchon's 2006 novel, Against The Day, mention is made of a "Captain Igor Padzhitnoff" (presumably pronounced the same as Pajitnov) who's preferred method of causing trouble was "to arrange for bricks and masonry, always in the four-block fragments which had become his 'signature,' to fall on and damage targets designated by his superiors
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